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Electronic Conductive Metal-Organic Frameworks (EC-MOFs) materials are a new class of conductive porous crystalline materials that are self-assembled by metal ions or metal ion clusters and organic ligands via coordination bonds. A class of crystal materials with porosity, selectivity and semiconducting properties, EC-MOFs have been widely used as active functional components in new type of crystal because of its rich designable crystal structure and adjustable electronic band structure. Of field effect transistors, lithium batteries, supercapacitors, gas sensors and other semiconductor electrical devices.However, most of the reported applications of EC-MOFs materials are in the form of powder or thick film, huge Particle size and grain boundaries limit the transport of electrons and species in electrical devices.It is well known that the quality of thin films is one of the key determinants of high performance devices.Li-layer-by-layer (LbL) liquid phase epitaxy Method is an effective method for the preparation of films with uniform thickness and controllable MOFs.However, only some of them have special secondary structures (second b MOFs can be prepared by the LbL method.The controllable epitaxial growth by LbL method for EC-MOFs conductive films has not been reported until now.
Supported by the National Natural Science Foundation of China, the research equipment development project of the Chinese Academy of Sciences and the CAS Key Project of Frontier Science, the research group headed by Xu Gang, researcher of the State Key Laboratory of Structural Chemistry of the Chinese Academy of Sciences, Progress has been made in the research of durable EC-MOFs films and devices.
The group of assistant researcher Yao Mingshui and master Lu Xiaojing using LbL spray method for the first time to prepare the thickness and quality of EC-MOFs film controllable in the upper nanoscale EC-MOFs film growth based on a good chemical stability of the hexagonal system EC-MOFs material Cu3 (HHTP) 2 (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene), the material in the ab direction Cu-HHTP two-dimensional conductive structure formed along the c-axis direction Slightly slip ABAB stacking modeled honeycomb microporous structure, the membrane conductivity of up to 2 S · m-1.The prepared Cu3 (HHTP) 2 film is not only a single layer thickness can be controlled ~ 2nm, the surface roughness degree<5nm, 同时垂直于基底方向沿[001]方向具有良好结晶取向. 这些优点赋予其在高效电学器件方面巨大的应用潜力, 作为应用实例, 在预制金叉指电极的蓝宝石基片上生长的Cu3(HHTP)2薄膜被直接应用于室温化学电阻型气敏传感器. 实验结果表明, 在室温下, 薄膜越薄, 气体扩散与电荷传输能力越好, 对气体的检测能力越强. 其中20nm厚度的Cu3(HHTP)2薄膜的性能最佳, 100ppm室温电阻变化可达129%, 并对氨气表现出良好的选择性和长期稳定性 (96天后仍保持~90%响应值) . 分析显示, p型响应来源于还原性氨气吸附导致的费米能级提升 (n型掺杂效果) , 载流子浓度下降, 导致电流下降; 高选择性主要源于氨气与Cu位点和配体的强相互作用. 同时, 由于薄膜表面光滑, 且颗粒紧密, 取向堆积, 进一步提升电荷传输和传质能力, 因而比已报道的Cu3(HHTP)2厚膜传感器响应值提升一个数量级以上.
Relevant results published in the "German Applied Chemistry", and was selected as the cover of the current period.Research work by Confucius, Nanologists and research into the academic platform of concern and coverage.
